This invention relates to automotive elements for an air bag or the like, and more particularly to a circuitry assembly and an electrical junction box having connectors for such automotive elements.
FIGS. 10A and 10B show a branch structure of flat cables disclosed in Japanese Patent Publication No. 8-17259A.
Each of flat cables 61 and 62 comprises an insulative layer 63 made of synthetic resin, and a plurality of cable conductors 64 embedded in the insulative layer 63. Hole portions 65 are formed in one side (face) of the insulative layer 63 by partly removing the insulative layer 63, and are disposed in registry with the cable conductors 64, respectively. The hole portions 65 in the flat cable 61 are opposed respectively to the hole portions 65 in the flat cable 62, and the corresponding two cable conductors 64 of the two flat cables are connected together by a solder layer 66 disposed in the hole portions 65.
FIG. 11 shows an electrical junction box disclosed in Japanese Utility Model Publication No. 7-9023U.
This electrical junction box 71 comprises: an upper cover 72 and a lower cover 73 which are made of synthetic resin to jointly form a box body; a wiring board 74 and a bus bar wiring board 75 which are accommodated between the two covers 72 and 73 in a stacked manner.
The wire wiring board 74 comprises: an insulative board 76 made of synthetic resin; a plurality of sheathed wires 77 laid on a surface of the insulative board 76; and terminals 78 which extend through the insulative board 76 to which the wires 77 are press-fitted. A press-fitting portion 78a is formed at one end of the terminal 78 while a male tab-like electrical contact portion 78b is formed at the other end thereof.
The bus bar wiring board 75 comprises an insulative board 79 and a plurality of bus bars 80 installed on a surface of the insulative board 79. The bus bar 80 has an integral male tab-like terminal 81 extending upwardly or downwardly therefrom.
The terminals 78 and 81 project into associated housings 82 and 83 formed at the upper cover 72 and the lower cover 73, and the terminals 78 and 81 are combined with the housings 82 and 83 to form connectors. External connectors (not shown), connected to external wire harnesses, are connected to these connectors. Instead of such external connectors, fuses or relays can be connected to the terminals within the housings 82 and 83 through relay terminals.
In the above branch structure, however, since the hole portions 65 are formed only in one side of the insulative layer 63 as shown in FIG. 10A, and the corresponding two cable conductors 64 are connected together through the solder layer 66 as shown in FIG. 10B, much time and labor are required for this connecting operation. And besides, accuracy is required for the operation, and there has been an anxiety that the efficiency of the operation is low.
In the electrical junction box 71 shown in FIG. 11, the plurality of rigid insulative boards 76 and 79, many wires 77 and the relatively-heavy bus bars 80 are used, and therefore there have been encountered problems that the structure is bulky and heavy, that the number of connection circuits is limited and that much time and labor are required for the operation for installing the wires 77 and for the operation for installing the bus bars.